1. Technical Field
This disclosure is directed to data transmission, and more particularly, to calibrating data transmissions to a clock signal.
2. Description of the Related Art
Eye patterns, or eye diagrams, are graphic illustrations that illustrate times and amplitudes at which a digital signal can be sampled at its correct value. In various types of systems that include data transmissions, sampling of signals (based on a clock signal) near a center of an eye, in terms of time, may be desirable. This may provide a signal with a sufficient amount of both setup and hold time, while also rendering it less susceptible to noise.
In memory systems, a number of data bits may be transmitted in parallel. Each of the data bits may be sampled using a clock signal that is common to all. Accordingly, the data signals may result in the various data signals being at different points of their respective eye patterns. Calibration routines may be performed such that the data signals are sampled at a receiver (e.g., at the memory) so that they are near the center of their respective eye patterns. Calibrations may be performed by sampling the data signals at various points in what amounts to sweeping the clock signal across the eye pattern, from one side of the eye pattern to the other while conducting reads of the memory.